Feature/3134 add option for additional logo in footer

[precious-onyenaucheya-ons]

What is the context of this PR?

Fixes #3134 This PR updates the footer component to support an additional logo, allowing for two logos instead of just one. It introduces link param for each logo and offers an alternative layout option to display the logos on opposite sides of the footer. The default layout positions the logos next to each other. Additionally, the implementation is aligned with the header component's multipleLogo feature to ensure consistency across the application. The focus and hover states are also adjusted to avoid extra underlines and to ensure the highlight color wraps only the SVG.

BREAKING CHANGE Services using the poweredBy param with the footer component will now need to update that param to footerLogo object in their config.

How to review this PR

• Spin up the website and head to the 'footer' component, the example-footer-with-extra-poweredby-logo on the page is the one to look at.
• Check for multiple logos: Verify that the footer displays two logos as expected, with appropriate links set for each logo.
• Review layout options: Confirm that the default layout positions the logos next to each other and test the alternative layout option where the logos are displayed on opposite sides of the footer.
• Test focus and hover states: Ensure that the focus and hover states do not create an extra underline and that the highlight color wraps only the SVG, not its margin.
• run yarn test --testNamePattern="macro: footer" & yarn test-visual

Checklist

This needs to be completed by the person raising the PR.

• [x] I have selected the correct Assignee
• [x] I have linked the correct Issue

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[balibirchlee]

I thought that we were wanting to rename 'poweredby' - and follow the naming convention of the header section with the logo1 logo2 rather than 'additionalPoweredByLogo'. Given that the functionality has come from the team, having it as a breaking change / incorporating it into plans for deprecation makes more sense to me, as there's no external pressure for it to be merged asap - I worry about creating more tech debt

[precious-onyenaucheya-ons]

@rmccar Previously, a margin-bottom was set for the default ONS logo if no powered-by logo was provided. However, if a powered-by logo was included, there was no margin-bottom. The difference in the snapshot is due to my adjustment: I have added the margin-bottom to be consistently applied in both scenarios.

[SriHV]

In the example-footer-with-alternative-organisation one, the logo is not focused right. Can you check this?